The present invention is concerned with the field of anesthetic injection of the palatal tissue and more particularly to a method and instrument which can be readily used by dentists, for example, to deaden or eliminate the pain associated with the penetration of the needle into the relatively thin and sensitive palatal tissue. Various instruments have been proposed over the years to aid in the injection of anesthetics or the withdrawal of blood, as set forth in the following prior art patents:
______________________________________ 1,561,116 Silliman 2,945,496 Fosdal 4,795,344 Brewer, Jr. 4,836,781 Meinershagen ______________________________________
None of the foregoing patents are, however, particularly concerned with injection at the palatal foramina where the nerves are exposed in the bone and the soft tissue is fibrous and taut. In the Fosdal U.S. Pat. No. 2,945,496, a dental instrument is suggested for gum tissue. In this instrument, a foot having top and bottom openings is placed on the gum tissue with only enough pressure to seal the opening for the application of suction. The upper opening in the foot is covered with a jacket of transparent material and, when the gum tissue is sucked up into the foot through the bottom opening, a hypodermic needle is inserted through the jacket and into the gum tissue to progressively feed a pain killing drug into the tissue. The Fosdal patent postulates that suction drawing the tissue into the interior of the foot causes the tissue to become taut, firm and immobile and that this preconditioning minimizes the shock of needle penetration. In effect, the instrument used applies a negative pressure which, as will become apparent, is the antithesis of what the present method teaches. The instrument requires movable tissue such as to be found in the gums but not in the thin, taut palatal tissue. The other patents cited are also considered not materially pertinent to the invention claimed, which is neither singularly nor combinatively disclosed or suggested in these prior art patents.
Another method which has been recommended is the use of a swab stick at a site adjacent the area to be injected, while the needle is inserted adjacent to the tissue which is pressed until it blanches by the swab stick. The swab stick may undesirably leave cotton fibers in the tissue and, more importantly, presses only a very small spot at one side of the tissue which is to be injected.